Spodoptera litura larvae are attracted by HvAV-3h-infected S. litura larvae-damaged pepper leaves.

BACKGROUND: Herbivore-induced plant volatiles (HIPVs) are important self-defense outputs of pepper plants to resist insect pests. Ascoviruses are pathogenic to the larvae of most lepidopteran vegetable pests. However, whether Heliothis virescens ascovirus 3h (HvAV-3h)-infected Spodoptera litura larvae can change pepper leaf HIPVs is not well understood. RESULTS: Spodoptera litura larvae preferred S. litura-infested leaves, and this preference was stronger with longer duration of S. litura infestation. In addition, S. litura larvae significantly chose pepper leaves damaged by HvAV-3h-infected S. litura over the healthy pepper leaves. Results also showed that S. litura larvae preferred leaves mechanically damaged and treated with oral secretions from HvAV-3h infected-S. litura larvae in a simulation test. We captured the volatiles emitted by leaves under six treatments. Results showed that the volatile profile changed with the different treatments. Testing of volatile blends, prepared to the proportion released showed that the blend from simulated HvAV-3h-infected S. litura larvae-damaged plants was the most attractive to S. litura larvae. Further, we also found that some of the compounds significantly attracted S. litura larvae at specific concentrations. CONCLUSION: HvAV-3h-infected S. litura can alter the release of HIPVs in pepper plants and thus become more attractive to S. litura larvae. We speculate that this may be due to alterations in the concentration of some compounds (such as geranylacetone and prohydrojasmon) affecting the behavior of S. litura larvae. © 2023 Society of Chemical Industry.

Repellence or attraction: secondary metabolites in pepper mediate attraction and defense against Spodoptera litura.

BACKGROUND: Resistance to insect pests is an important self-defense characteristic of pepper plants. However, the resistance of different pepper cultivars to Spodoptera litura larvae, one of the main insect pest species on pepper, is not well understood. RESULTS: Among seven pepper cultivars evaluated, cayenne pepper 'FXBX' showed the highest repellency to third instar S. litura larvae, Chao tian chili pepper 'BLTY2' showed the lowest repellency. Plant volatiles (1-hexene, hexanal, ß-ionone, (E,E)-2,6-nonadienal, and methyl salicylate) affected host selection by S. litura. Among these, 1-hexene, hexanal, and ß-ionone at concentrations naturally-released by pepper leaves were found to repel S. litura. Interestingly, S. litura larvae fed on the larva-attracting pepper cultivar, (BLTY2) had an extended developmental period, which was about 13 days longer than larvae fed on FXBX. Besides, the survival rate of larvae fed on BLTY2 was 22.5 ± 0.0%, indicating that the leaves of BLTY2 can kill S. litura larvae. Correlation analysis showed that larval survival rate, emergence rate, female adult longevity, and pupal weight were positively correlated with the vitamin C, amino acids, protein, cellulose, and soluble sugar contents, but were negatively correlated with wax and flavonoids contents. CONCLUSION: We identified two different modes of direct defense exhibited by pepper cultivars against S. litura. One involves the release of repellent volatiles to avoid been fed on (FXBX cultivar). The other involves the inhibition of the growth and development or the direct killing of S. litura larvae which feeds on it (BLTY2 cultivar). © 2022 Society of Chemical Industry.

Chinese Cabbage Changes Its Release of Volatiles to Defend against Spodoptera litura.

Plants respond to herbivorous insect attacks by releasing volatiles that directly harm the herbivore or that indirectly harm the herbivore by attracting its natural enemies. Although the larvae of Spodoptera litura (the tobacco cutworm) are known to induce the release of host plant volatiles, the effects of such volatiles on host location by S. litura and by the parasitoid Microplitis similis, a natural enemy of S. litura larvae, are poorly understood. Here, we found that both the regurgitate of S. litura larvae and S. litura-infested cabbage leaves attracted M. similis. S. litura had a reduced preference for cabbage plants that had been infested with S. litura for 24 or 48 h. M. similis selection of plants was positively correlated with the release of limonene; linalool and hexadecane, and was negatively correlated with the release of (E)-2-hexenal and 1-Butene, 4-isothiocyanato. S. litura selection of plants was positively correlated with the release of (E)-2-hexenal, 1-Butene, 4-isothiocyanato, and decanal, and was negatively correlated with the release of limonene, nonanal, hexadecane, heptadecane, and octadecane. Our results indicate that host plant volatiles can regulate the behavior of S. litura and M. similis.

The complete mitochondrial genome of Lyssa zampa (Lepidoptera: Uraniidae).

The complete mitochondrial genome (mitogenome) of Lyssa zampa was first reported. It is 15,314 bp in length (GenBank accession number: MW435592) and consists of 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes. The nucleotide composition is A (41.5%), C (11.1%), G (7.4%), and T (40.0%). Based on the sequences of complete mitogenome from 12 geometroid species and three drepanoid species as ingroups, and two noctuoid species as outgroups, the phylogenetic tree was constructed. The results showed that the closest relationship between Uraniidae and Epicopeiidae was strongly supported by Bayesian posterior probabilities values of 0.99.

Well-Defined Mo2C Nanoparticles Embedded in Porous N-Doped Carbon Matrix for Highly Efficient Electrocatalytic Hydrogen Evolution.

On the design of efficient and affordable electrocatalysts for water reduction half reaction, this paper fabricates molybdenum carbide nanoparticles uniformly loaded in highly porous N-doped carbon matrix derived from polyaniline-molybdate monolith with the use of graphitic carbon nitride (g-C3N4) as template. The obtained molybdenum carbide-carbon hybrid catalysts (MoC@NCS) exhibit extraordinarily electrochemical hydrogen evolution activity with a small overpotential of 89 and 81 mV to deliver a current density of 10 mA cm-2 in alkaline (1.0 M KOH) and acidic (0.5 M H2SO4) medium, respectively, even comparable to noble-metal Pt/C benchmark. Specially, MoC@NCS also shows excellent long-term durability in alkaline or acidic electrolyte. Furthermore, the obtained carbon matrix (NCS) featuring high content of N dopants and hierarchically porous architecture exhibits high catalytic efficiency for oxygen evolution reaction in alkaline electrolyte. For a further step, the obtained NCS coupled with the MoC@NCS, working as anodic and cathodic electrodes, in a two-electrode alkaline electrolyzer for overall water splitting, which can obtain a current density of 10 mA cm-2 at 1.69 V, along with robust operation durability. The synergistic effect of the porous carbon matrix of high nitrogen content and the molybdenum carbide nanoparticles of uniform distribution, together with hierarchically porous structure, should be responsible for the outstanding electrocatalytic HER performance. This work presents an easy and cost-effective strategy to prepare molybdenum-based materials with controlled size for electrocatalytic hydrogen evolution.

Uniquely integrated Fe-doped Ni(OH)2 nanosheets for highly efficient oxygen and hydrogen evolution reactions.

Developing high-efficiency electrocatalysts for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is vital for the production of hydrogen on a large scale by electrocatalytic splitting of water. Herein, Fe-doped Ni(OH)2 nanosheets directly grown on commercial Ni foam (FeNiOH/NF) were fabricated through a facile hydrothermal method in (NH4)2S2O8 aqueous solution containing iron salts. The integrated architecture with hierarchical pores is beneficial for exposing sufficient catalytically active sites and providing evaluated structural and electrical properties. In particular, the Fe-induced partial-charge-transfer greatly modifies the electronic structure of Ni(OH)2, which evidently promotes the electrocatalytic activity of the as-fabricated FeNiOH/NF for OER and HER. Thus, as an electrocatalyst for OER, FeNiOH/NF exhibits excellent activity with overpotentials of 271 and 318 mV to deliver current densities of 20 and 100 mA cm-2, respectively, with a small Tafel slope of 72 mV dec-1 in 1.0 M KOH, demonstrating the very high level of novelty and sufficient improvement over the current state-of-the-art IrO2 electrocatalyst. Most importantly, there is an increase in overpotential by only 23 mV during continuous reaction for over 20 h at an applied potential of 1.62 V to deliver current density of 500 mA cm-2. The as-fabricated electrocatalyst also enables high HER activity with robust stability. Finally, an overall water splitting current density of 10 mA cm-2 can be obtained at a cell voltage of 1.67 V in a two-electrode alkaline electrolyzer using FeNiOH/NF as both anode and cathode, along with impressive operation stability. This development with significant over the state-of-the-art IrO2 electrocatalyst can be widely extended to large-scale fabrication of versatile electrocatalysts for efficient water splitting technology.